Multimode pulse width modulation systems are those that can selectively provide leading edge modulation (LEM), trailing edge modulation (TEM) and dual edge modulation (DEM). While these systems are convenient in many applications they suffer from a number of disadvantages. Typically each mode, LEM, TEM, DEM is generated by a separate subsystem. LEM and TEM arrangements each require a separate ramp and DEM requires two ramps. In addition, in high-speed applications where pulses are to be generated alternately, sequentially in both halves of a clock cycle, for example, LEM and TEM require two ramp generators and DEM requires four ramp generators. In each instance two comparators are utilized with each ramp generator: the circuit is large and complex. Further, since each mode is generated from separate ramps, there is a certain loss of symmetry, accuracy and switching speed, as well as difficulty in synchronizing or aligning the pulses when switching between modes.